The field of invention relates generally to micro-fabrication of structures. More particularly, the present invention is directed to patterning substrates in furtherance of the formation of structures.
Micro-fabrication involves the fabrication of very small structures, e.g., having features on the order of micro-meters or smaller. One area in which micro-fabrication has had a sizeable impact is in the processing of integrated circuits. As the semiconductor processing industry continues to strive for larger production yields while increasing the circuits per unit area formed on a substrate, micro-fabrication becomes increasingly important. Micro-fabrication provides greater process control while allowing increased reduction of the minimum feature dimension of the structures formed. Other areas of development in which micro-fabrication has been employed include biotechnology, optical technology, mechanical systems and the like.
An exemplary micro-fabrication technique is shown in U.S. Pat No. 6,334,960 to Willson et al. Willson et al. disclose a method of forming a relief image in a structure. The method includes providing a substrate having a transfer layer. The transfer layer is covered with a polymerizable fluid composition. An imprint device makes mechanical contact with the polymerizable fluid. The imprint device includes a relief structure, and the polymerizable fluid composition fills the relief structure. The polymerizable fluid composition is then subjected to conditions to solidify and polymerize the same, forming a solidified polymeric material on the transfer layer that contains a relief structure complimentary to that of the imprint device. The imprint device is then separated from the solid polymeric material such that a replica of the relief structure in the imprint device is formed in the solidified polymeric material. The transfer layer and the solidified polymeric material are subjected to an environment to selectively etch the transfer layer relative to the solidified polymeric material such that a relief image is formed in the transfer layer.
An important characteristic with accurately forming the pattern in the polymeric material is to reduce, if not prevent, adhesion of the polymeric material, and/or, transfer layer, to the imprint device. These are referred to as release characteristics. In this manner, the pattern recorded in the polymeric material and/or transfer layer, is not distorted during. separation of the imprint device therefrom. To improve the release characteristics, Willson et al. form a release layer on the surface of the imprint device. The release layer adheres to the imprint device and to either the transfer layer or the polymeric material. Providing the transfer layer with improved release characteristics minimizes distortions in the pattern recorded into the polymeric material and/or the transfer layer that are attributable to imprint device separation.
It is desired, therefore, to improve the release characteristics of an imprint device employed in imprint lithography processes.